In the past, a system for controlling/monitoring equipments connected to a non-IP network by a terminal device connected to an IPv6 network has been proposed. This system has a gateway for enabling communication between the non-IP network equipments and the IPv6 network terminal device by acquiring identification information and interface ID of the non-IPv6 network equipments as well as network ID for the IPv6 network, generating IPv6 addresses from these IDs, and managing the correspondence between the generated addresses and the identification information. By way of this gateway, the equipments can be controlled or monitored by the terminal device.
For example, this kind of network system is disclosed in Japanese Patent Early Publication No. 2003-60664. In this system using the non-IPv6 equipments, an IPv6 network terminal device sends a packet with a header including destination IPv6 address, and the IPv6 address is allocated to the non-IPv6 equipment at a gateway. Therefore, when the terminal device accesses plural equipments, it becomes necessary to generate the IPv6 address corresponding to each of the equipments. That is, it is needed to take account of the IPv6 address. In addition, even when increasing the number of the equipments for performing the same operation, it becomes necessary to newly generate the IPv6 address corresponding to the added equipment. Therefore, there are inconveniences that the plural equipments cannot be controlled or monitored by use of a single identifier, and plural identifiers cannot be allocated to a single equipment. Furthermore, it is not possible to flexibly cope with an increase in the number of the equipments for providing services.